In a previous research project we have established that problem-solving skills learned in a task-oriented apprenticeship training context are effectively utilized by tribal tailors in the solution of new and unfamiliar problems. The present proposal is designed to explore the question: given that learning transfer occurs, what are its limits? That is, at what range of dissimilarity do problems become so unusual that the tailors' problem-solving principles are not general enough to produce correct solutions. The problem-solving skills to be investigated in the field research project proposed here are arithmetical skills. In designing problems to test these skills it has become apparent that at least three dimensions (familiarity, numerical difficulty, and abstractness) must be considered in deciding how similar a test problem is to a daily work problem. The test to be administered in the field will explore the effects of increasing dissimilarity of problems along each of the three dimensions. The test will be administered to a sample of Vai and Gola traditional tribal tailors and their apprentices in Monrovia, Liberia, and to a matched group of non-tailors. Multiple regression analysis will be used to test explanatory models of differences in the performances of the tailors. Independent variables will include age, starting age of apprenticeship, years of tailoring experience, years of education, stage of skill training, and quality of apprenticeship. This method of analysis allows us to ask a number of important questions about the effects of alternative forms of education on the development of cognitive skills: a) What are the relative contributions of apprenticeship training and formal education to the formation of transferable, general problem-solving skills? b) Do schooling and apprenticeship training teach the same skills along the three dimensions of dissimilarity? c) Does learning transfer extend to the same range of generality in both cases?